Resective Epilepsy Surgery for Drug-Resistant Focal Epilepsy: A Review

Abstract

IMPORTANCE: Epilepsy surgery is indicated for patients with focal seizures who do not respond to appropriate antiepileptic drug therapy consisting of 2 or more medications. OBJECTIVES: To review resective surgery outcomes for focal epilepsy, to identify which patients benefit the most, and to discuss why epilepsy surgery may not be universally accepted. EVIDENCE REVIEW: Medline and Cochrane databases were searched between January 1993 and June 2014 for randomized clinical trials, meta-analyses, systematic reviews, and large retrospective case series (>300 patients) using Medical Subject Headings and indexed text terms. Fifty-five articles were included. Subpopulations and prognostic factors were identified. Systematic reviews for cognitive, psychiatric, quality-of-life, and psychosocial outcomes were included. FINDINGS: Two randomized clinical trials enrolling 118 patients with temporal lobe epilepsy found greater freedom from seizures with surgery when compared with continued medical treatment (58% vs 8% [n = 80] and 73% vs 0% [n = 38], P < .001). Nine systematic reviews and 2 large case series of medically refractory patients treated with surgery reported seizure-free outcomes in 34% to 74% of patients (median, 62.4%). The remainder of systematic reviews and meta-analyses examined subpopulations. Epilepsy surgery was less effective when there were extratemporal lesions, the epilepsy was not associated with a structural lesion, or both. Seizure-free outcomes were similar between children and adults. Hippocampal sclerosis and benign tumors were associated with better outcomes relative to other pathologies. Similar procedures such as selective amygdalohippocampectomy and temporal lobectomy for temporal lobe epilepsy were associated with subtle differences in seizure and neuropsychological outcome. There is low perioperative mortality (0.1%-0.5%) from epilepsy surgery. The most frequent neurologic complication is visual field defect occurring from temporal lobe resection. Quality of life improved after surgery but improved the most in patients who were seizure-free after surgery. CONCLUSIONS AND RELEVANCE: Epilepsy surgery reduced seizure activity in randomized clinical trials when compared with continued medical therapy. Long-term cognitive, psychiatric, psychosocial, and quality-of-life outcomes were less well defined. Despite good outcomes from high-quality clinical trials, referrals of patients with seizures refractory to medical treatment remain infrequent.